H. J. Spanner disclosed in his U.S. Pat. No. 2,265,323 a "Gas and Metal Vapor Discharge Tube and Means for Preventing Flicker Therein" by using a special type of self-heated solid activated electrodes, and a means for controlling the heat dissipation in order to obtain a high vapor pressure of the vaporized metals, which however may have the following drawbacks:
1. In order to fit so many special self-heated electrodes, a specially-designed tube must be provided to limit its versatile applications since the tubes out of order must also be replaced with specially designed tubes, causing maintenance problems.
2. It will consume much electric energy for warming up the so many electrodes. For increasing temperature required by the tubes, the service life of the lamp may be shortened.
3. If environmental temperature is too low, it may influence the ignition of the tube.
The present inventors have found the defects of a conventional gas discharge tube and invented the present stable ignition means for fluorescent lamp or the like.